1. Field of the Invention
This invention relates to the production of nut butter products and related products. More particularly, the invention relates to a method of producing peanut butter products that provides a creamy product with only one grinding step, and products made by the method.
2. Description of the Related Art
The high nutritional value and good taste make nut butters, particularly peanut butter, an important food product in many households. New methods to improve the consumer appeal of peanut butters in respect to taste and texture are continually being sought. These include methods of improving nut butters having typical fat levels (approximately 500) and those having reduced fat levels.
Peanuts, cashews, almonds, walnuts, pecans, and the nut butter products made from them, are known sources of vegetable protein and other nutrients. Although there is a dietary need for protein, and vegetable proteins provide a ready economic source, nuts and nut products also contain high amounts of fat. Peanuts, for example, comprise over 50% fat and account for over 90% of the fat in peanut butter. Increasingly, people are reducing the amount of fat in their diets in response to information linking health problems with high fat diets. Consumption of nuts and nut products is therefore reduced by those seeking lower fat sources of protein. Since nuts represent a good source of protein, and peanut butter in particular is a popular product, a need exists for a method of making the desired products while reducing the amount of fat.
The terms “nut butter” and “peanut butter” in particular as used herein are intended to include any peanut butters (21 C.F.R. 164.150), peanut spreads (21 C.F.R. 102.23(a)) and imitation peanut butters (21 C.F.R. 102.23(b)) and is not meant to be limited in any manner by regulatory definitions.
Methods of making peanut butter are described in the patent literature such as in U.S. Pat. No. 3,619,207 (Dzurik et al.) which describes an improved peanut paste ingredient and a method of making same using a homogenizer. U.S. Pat. No. 4,004,037 (Connick) describes a method of grinding peanuts in the presence of solid carbon dioxide to reduce oxidation of the peanut oil during grinding and reduce the amount of dissolved oxygen, thereby resulting in improved stability and flavor.
U.S. Pat. No. 5,079,027 (Wong et. al.) describes a peanut butter composition made from a nut paste. The nut butter, made by this method does not share the characteristics and qualities of the nut butter desribed herein, owing, in part, to the difference in particle size distribution.
Various methods have been developed to reduce the amount of fat in nut butter products such as peanut butter. These methods generally follow one or a combination of two approaches, those that use a normal amount of nuts in the mix but reduce the fat in the nuts and those that keep the fat in the nuts but replace some of the nuts with bulking agents. Several patents have issued showing methods and compositions improving on these general approaches.
U.S. Pat. No. 5,240,734 (Izzo et al.) discloses a composition and method of making a reduced fat peanut butter in the form of a water-in-oil emulsion which contains a continuous peanut butter oil phase comprised of peanut butter and a protein complexing agent to maintain the consistency of the continuous peanut butter oil phase, and a discontinuous aqueous coagulated protein phase to reduce the fat content of the peanut butter which contains a coagulable dairy or vegetable protein and a protein coagulating agent.
U.S. Pat. No. 5,230,919 (Walling et al.) discloses a reduced fat nut or oilseed butter composition which contains from about 40% to about 67% nut solids, from about 33% to about 45% oil, and from 0 up to about 4% stabilizer, 40% bulking agent, 8% flavorant and 3% emulsifier. The nut butter of Walling et al. does not have that characteristics of the nut butter obtained through the one-step process described herein owing, in part, to differences in particle size distribution.
U.S. Pat. No. 5,302,409 (Franklin) discloses a reduced fat peanut butter which is obtained by removing oil from ground peanuts preferably by centrifuging the ground peanuts until a supernatant oil layer is formed above the ground peanuts and separating the ground peanuts from the supernatant oil layer.
A high protein and/or low fat nut spread is made according to U.S. Pat. No. 5,433,970 (Wong et al.) by employing a homogenizer and a colloid mill or series of colloid mills to obtain a desired particle size and viscosity.
U.S. Pat. No. 4,828,868 (Lasdon et al.) discloses a low calorie, low fat peanut butter like product wherein unroasted, defatted peanut flour is milled in water to a smooth, free flowing consistency and then cooked at a temperature of at least 175° F. but below the boiling point of the water/flour mixture. The patent discloses that the resulting product has a water content of 45 to 55 percent and a fat content of from 1 to 25 percent.
The method of the present invention represents an improvement in the manner of grinding which releases a maximum amount of native oil from the nut matrix while reducing the particle size of the solid components. The free oil which is released is hypothesized to coat the solid particles improving mouth feel “slip” characteristics. The amount of available free oil lowers product viscosity which imparts processability and machinability.
The amount of oil expelled or the degree of particle size reduction can be manipulated according to the invention to produce, in a cost effective way, an organoleptically pleasing product. The nut butter composition of the invention has improved spreadability unlike that of other commercial products.
The method of the present invention represents a further improvement on the approach that seeks to reduce the fat in nut butters by replacing some of the nuts in the mixture with bulking agents. The entire mixture of ingredients is ground in a mill which produces high centrifugal forces thereby grinding all of the ingredients into an acceptable particle size while expelling fat out of the nut matrix and producing a nut butter with the desired mouth feel and taste.
An improvement provided by the invention is that the entire mixture can be ground in one step while producing a creamy product. A one step method of grinding is especially useful for the production of reduced fat peanut butters where the lack of available oil in the mixture presents problems with forming a creamy product which is necessary for processing with conventional finishing and packaging operations. One or more additional grinding steps can be used if more fluidity is desired.
A further improvement provided by the invention is that the size and form of the major and minor ingredients can be as large as is commercially and economically feasible without affecting grinding in respect of overall particle size reduction or the amount of oil expelled. Accordingly, materials in their most raw form such as flakes, slivers, spheres, granules and the like can be used without pre-treatment, such as by grinding.
All percentages and parts expressed herein are on a weight/weight basis unless specified otherwise.